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    <title>Document</title>
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<script>
    //【2.31】设置函数参数的默认值
        //ES5方式
        function fn(name,age){
            name = name || "tom";
            age = age || 17;
            console.log(name + "," + age);
        }
        //ES5 + 类型检查
        function fn2(name,age){
            name = (typeofname !='undefined'? name:'tom');
            name = (typeofage !='undefined'? age:17);
            console.log(name + "," + age);
        }
        //ES6方式
        function fn3(name='tom',age=17){
            console.log(name + "," + age);
        }               
                            
        fn();
        fn2();
        fn3();

</script>
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